1. Field of the Invention
The present invention relates to a layout setting device that sets layout of a target lens shape used as a processing shape with respect to an eyeglass lens when the lens is processed for fitting the lens to an eyeglass frame, an eyeglass lens processing apparatus, an eyeglass frame measuring device, and a cup attaching device, each having the layout setting device.
2. Description of the Related Art
When spectacles are formed by an eyeglass frame and an eyeglass lens, an optical center of a lens for a left eye generally corresponds to a pupil center of a user's left eye and an optical center of a lens for a right eye generally corresponds to a pupil center of a user's right eye. Accordingly, if geometric centers of left and right rim shapes (hereinafter referred to as target lens shapes) of the frame correspond respectively to the left and right pupil centers of the user when the user wears the frame, it is enough to fit the lenses to the frame so that the optical centers of the lenses correspond to the geometric centers of the target lens shapes of the frame. However, in actual, the geometric centers of the target lens shapes of the manufactured frame generally do not correspond to the pupil centers of the user. For this reason, when the periphery of the lens is processed to fit the lens to the frame, the geometric center of the target lens shape of the frame is positioned with respect to the optical center of the lens, that is, layout of the target lens shape with respect to the lens is set based on deviation in a lateral (substantially horizontal) direction and deviation in a longitudinal (substantially vertical) direction between the geometric center of the target lens shape of the frame and the pupil center of the user. Accordingly, a device for setting the above-mentioned layout is provided in an eyeglass lens processing apparatus called as an edger, an eyeglass frame measuring device called as a tracer, or a cup attaching device called as a blocker.
The deviation in the lateral direction (hereinafter referred to as lateral deviation (shift amount)) between the geometric center of the target lens shape of the frame and the optical center of the lens is obtained from a difference between a distance between the pupil centers of the user (hereinafter referred to as a pupillary distance: PD) and a distance between the geometric centers of the target lens shape of the frame (hereinafter referred to as a frame pupillary distance: FPD). In particular, it is preferable that the lateral deviation is obtained in consideration of warp in the case of a frame with significantly warped rims. For this reason, a technology, in which the lateral deviation (shift amount) is obtained (corrected) based on the warp angle of the frame (rim), has been proposed as disclosed in, for example, U.S. Pat. No. 5,333,412 (JP-A-4-93164).
As disclosed in U.S. Pat. No. 5,333,412 (JP-A-4-93164), in the case of a frame having rims, the warp angle is obtained from three-dimensional shape data of the rims, which is measured by the eyeglass frame measuring device. However, in the case of a rimless frame, a template (pattern) for the rimless frame or a demo lens (model lens) is generally measured by the eyeglass frame measuring device. Since two-dimensional shape (target lens shape) data is obtained from the measurement, the warp angle is not obtained.
Meanwhile, the warp angle of the rimless frame, to which the demo lens is fitted, may be visually confirmed using a protractor. However, preparation of the protractor is troublesome.